1. Field of the Invention
This invention relates generally to attaching systems, and more particularly, to an improved squeegee attachment system for a printing machine to improve the application of ink during a single stroke in a silk screening process.
2. Description of Prior Art
As is well known, many types of materials and products may be printed on utilizing what is referred to as stenciling or silk screening. Many printing applications, such as the silk screening of printed circuits, or intricate designs having a multiple of colors, require a high degree of precision in which the printing paste or ink has to be carefully spread and applied. Silk screen printing is well known in the industry, and may be done manually or by automated machines. The automated printing machines normally utilize one or more print heads each of which hold a single squeegee in place to press the ink or paste through the screen during a stroke. That is, in the automated machines, a print head assembly holding a squeegee is operatively associated for movement into and out of printing relationship with one or more pallets as the pallets are mechanically indexed and maintained in a horizontal plane as they pass the print head.
One known printing machine in which a silk screening may be used, is disclosed in U.S. Pat. No. 5,533,445 to Bill, issued on Jul. 9, 1996. FIGS. 5-7 of this patent shows an improved print head 13. A number of these improved print heads may be slidably mounted on cross bars 30, so as to be translatable into selected positions. A silk screen 32 is slidably supported in a channel or frame holder 34 secured below or underneath the print head 13. A printing squeegee 44 is removably and rotatably secured to a lower end of a rotatable face place 45 mounted to the front of the print head 13. Rotation of the front plate 45 will rotate or lower the printing squeegee 44 downwardly, toward the screen 32. This downward rotation occurs after a specifically shaped flood cycle, during which a specifically shaped flood bar 50 presses ink into the screen 32. During the printing cycle, the downwardly rotated printing squeegee 44 presses the spread ink through the screen onto the item being printed, as the squeegee is translated over the ink in the screen by movement of the print head 13. The flood bar or plate 50 is preferably formed so as to have angled side portions to sweep all ink toward the center, or inwardly, when moved across the screen during the flood cycle, before printing by the printing squeegee. This flood bar is preferably mounted to the print head 13 in a position, such as the front thereof, so as to produce the best operating results during the flood cycle or stroke.
Although this known machine produces improved results, multiple strokes are sometimes required to lay down sufficient ink. Therefore, there exists the need in the art for an improved squeegee attaching system, which allows an operator to utilize, interchangeably, a single squeegee or multiple spaced squeegees to eliminate multiple works, thereby decreasing cycle time and increasing throughput.